Happy New (Chinese) Year!

On Sunday, Feb. 14, while we were observing Valentine’s Day, a much bigger celebration got underway in the Far East.  That was the  Chinese New Year, the day when the Year of the Ox ended and the Year of the Tiger began.  And the celebration is still ongoing, as it lasts until the Lantern Festival on the 15th day of the month (this year, Feb. 28).

Lanterns
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Like most Americans, I learned the sky as imagined by westerners around the Mediterranean basin, with images from Babylon, ancient Egypt, ancient Greece and Rome, and star names preserved during the Middle Ages by Arabs. So I find it fascinating to think of an entirely different culture and how they imagined the night sky. The Chinese New Year celebration is a perfectly appropriate time to do this, especially since objects in the sky, in particular the moon and Jupiter, serve as the basis of the ancient Chinese calendar.

The date of Chinese New Year varies; it can occur as early as Jan. 21 or as late as Feb. 19. However, anyone familiar with the lunar cycle can easily predict the date for a given year. That’s because China’s New Year always begins with the second new moon after the winter solstice.

Our Gregorian calendar is a solar calendar, based on the apparent position of the sun (and thus, on the Earth’s orbit around the sun).  However, the apparent position of the sun compared to the stars is difficult to observe.  Much more readily observable are the phases of the moon.  Thus the Chinese, like many ancient cultures, adopted a lunar calendar, measuring months from new moon to new moon.  Unlike the Islamic or ancient Roman calendars, the Chinese calendar begins months with the dark of the moon–the day the moon is invisible, not the first slender crescent seen at dusk.

Full Moon
Creative Commons License photo credit: Andréia

It would be convenient if one year equaled an even number of phase cycles. In fact, however, the moon takes about 29.5 days to go through one phase cycle, so 12 such cycles is 354 days.  This is significantly less than the solar year of 365.25 days, so a purely lunar calendar quickly becomes disconnected from the seasons and useless as a guide for when to plant or harvest.   To keep their lunar months connected with the seasons, the Chinese added a rule: the second-to-last lunar month must contain the winter solstice.  If the old crescent moon of the eleventh lunar month is waning towards new and the winter solstice has not yet happened, that month is repeated.  Similar rules exist for the second lunar month (which must contain the spring equinox), the fifth lunar month (which must contain the summer solstice), and the eighth lunar month (which must contain the fall equinox).  Accordingly, the first new moon after the winter solstice always begins the last month in the Chinese year, and the second new moon after the solstice begins the next year.

Chinese astronomers noticed that every twelve years, Jupiter reappears next to the same stars.   (This is because Jupiter takes 11.86 years to orbit the Sun.)  There were twelve months in a typical Chinese year (although occasionally one was doubled, as explained above).  Also, the Chinese divided the day into twelve double-hours.  They used a system of twelve ‘Earthly Branches’ to designate the months of the year and the double-hours in a day.  Jupiter’s motion in the sky established a cycle of years analogous to the cycles of months and double-hours.  Thus Jupiter became the ‘Year Star’ (Suixing) and years, too, were designated with the Earthly Branches.

Lion Dance
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Later, as a mnemonic device, the Chinese began to associate the Earthly branches with animals.  (Sources disagree as to exactly when.)  Legends tell that Buddha (or the Jade Emperor) summoned all of the animals to him; each of the first twelve to appear became associated with an Earthly Branch.  The twelve animals are:

1) Rat  2) Ox  3) Tiger  4) Rabbit  5)Dragon  6)Snake  7)Horse  8)Sheep  9)Monkey  10)Rooster  11)Dog  12)Pig

The signs of the Chinese zodiac, then, unlike those of the western zodiac, are not constellations in the sky.  The most well known of the Chinese constellations are the 28 ‘lunar mansions.’  These are small groups of stars very roughly arrayed along the ecliptic, which is the apparent path of the sun, moon and planets across the sky.  As you’ll see in the links below, the Chinese used some stars, such as those in Orion, that are too far from the ecliptic for the moon to pass through them.  The 28 mansions were subdivided into four groups of seven; each group of seven represented one of four Chinese animals associated with the directions and the seasons:

1) The Blue/Green Dragon (Qing Long) of the East, associated with spring.  Note that the ancient Chinese color word qing was quite broad in meaning.  Blue and green were considered different shades of this broadly defined color.

2) The Red Bird (Zhu Que) of the South, associated with summer.   This mythical bird, with red and orange plumage, is distinct from the feng huang, also called the Chinese phoenix.

3) The White Tiger (Bai Hu) of the West, associated with autumn.

4) The Black Tortoise (literally Dark Warrior, Xuan Wu) of the North, associated with winter.  Xuan Wu was always shown as a tortoise with a snake wrapped around it, reflecting the folkloric belief that all tortoises were female and needed to copulate with snakes to reproduce.

Of the stars in tonight’s evening sky, those in Orion and Taurus form part of the White Tiger, while Gemini and the dimmer stars south and east of it belong to the Red Bird.

Along with the four large animals, Chinese astronomers defined three large constellations known as the three enclosures.  The largest of these is the ‘Purple Forbidden Enclosure‘ (Zi Wei Yuan) which includes all those stars near the North Pole of the sky which never set as seen from mid-northern latitudes.  The enclosure is ‘forbidden’ because it includes the North Star, which was the Emperor of Heaven because it always remains in one spot while other stars seem to go in circles around it, as if paying court.

The ‘Supreme Palace Enclosure‘ (Tai Wei Yuan) actually rises in the late evening in February.  Look east about 9 tonight for a set of stars in the shape of a backwards question mark.  We see this as the head of Leo, the Lion.  Rising under the backwards question mark is a right triangle of similar brightness.  For us, this is Leo’s hindquarters, but in China, it’s the northwest corner of the Supreme Palace enclosure.  The other side of this enclosure is a semi-circle of stars westerners recognize as part of Virgo, the Virgin.

The final enclosure, the ‘Heavenly Market Enclosure‘ (Tian Shi Yuan), won’t rise until very early in the morning in February, and isn’t in the evening sky until late May.  It centers on our constellations Ophiuchus and Serpens (Caput and Cauda), just north of the bright summer constellations Scorpius and Sagittarius.

So, I wish everyone a happy Year of the Tiger.  I’ll celebrate it by looking at the stars in a way I ‘m not accustomed to seeing them.

Go Stargazing! February Edition

Jupiter!
Creative Commons License photo credit: Joshua Bury

Jupiter leaves the evening sky this month.  You can still see it during the next two weeks if you face southwest at dusk and look for the brightest point of light there. Jupiter sets by 7:30 as February opens, so you must look soon after dusk to see it.   However, Jupiter sets earlier and earlier and appears lower and lower to the horizon each February night, and soon disappears into the sun’s glare.  On Tuesday, Feb. 16, observers with a clear view of the horizon during twilight can try to see a very close conjunction of Jupiter and Venus, which is slowly moving out of the sun’s glare.  By the end of the month, Earth and Jupiter are on opposite sides of the Sun and Jupiter is therefore invisible to us.

Mars has become an evening object.  It is now already up in the east-northeast by dusk.  Mars already outshines all stars in the night sky except the very brightest (Sirius), and will continue to brighten throughout February.  On Jan. 29, Mars came to opposition as Earth passed between Mars and the sun, putting Mars in our sky all night long.  Earth now starts to pull ahead of Mars on its faster orbit.  As a result, Mars is slightly dimmer each night for the rest of 2010.  However, during February, Mars remains about as bright as the brightest stars, and thus remains easy to see.

Saturn is now high in the southwest at dawn.  Although not as bright as Mars this month, Saturn is brightening as it approaches its own opposition in March.

Joseph Nollekens (1737 - 1823) Castor and Pollux front (V&A 2007)
Castor and Pollux
Creative Commons License photo credit: ketrin1407

Dazzling Orion is high in the south, reminding us that winter is here.  His belt points up to Aldebaran, the eye of Taurus, the Bull.  The Dog Stars, Sirius and Procyon, are below Orion in the east.  Sirius is the brightest star we ever see at night.  Gemini, the Twins, are to Orion’s left as he rises (and to his upper left once they appear to the south).  Look for two stars of equal brightness less than 5 degrees (three fingers at arms’ length) apart.  These are Castor and Pollux, marking the twins’ heads.  High in the northeast is Capella, the sixth brightest star ever seen at night.  On February and March evenings, look below Sirius and a bit to its right for Canopus, the second brightest star we ever see at night. This star is in the keel (bottom) of the legendary ship Argo.  Canopus is so far south that most Americans never get to see it.  We, however, are far enough to the south that it barely rises for us, remaining low on the southern horizon.

Moon Phases in February 2010:

Last Quarter                  February 5, 5:50 pm
New Moon                      February 13, 8:52 pm
1st Quarter                     February 21, 6:42 pm 
Full Moon                       February 28, 10:37 am

The new moon of Feb. 13 is the second new moon after the winter solstice.  Accordingly, it marks the Chinese New Year, beginning the Year of the Tiger.  (Correct for the time zone difference, and you’ll see that the date is February 14 in China).

Chinese New Year - Dragon
Creative Commons License photo credit: ajagendorf25